Grinder



Aug. 28, 1923.

. -S. VENGRIN ET AL GRINDER Filed April 7, 1922 Patented Aug. 28, 1923.

T A ti .iff

STANLEY VENGBIN AND JOHN M. i

ii i

JOHNSON, F DULUTH, ll'II NNE SOTA.

GRIND R.

Application filed April 7, 1822.; Serial No. 558,263. i

and JOHN M. JOHNSON, each a citizen ofthe United States, residing at Duluth, in the county of St. Louis and State of Minnesota,

have invented certain new and useful Improvements in Grinders, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to grinders for hollow Chisels.

The object of the invention is to obviate the necessity of sharpening such chisels by hand which is frequently practiced at the present time and to accomplish a more desirable job of sharpening.

Other objects and advantages will appear in the further description of' the invention.

Referring to the accompanying drawing 0 in which like reference characters indicate like parts, I

Figure l is a sectional view with portions in elevation of one of the grinders having a; hollow chisel applied thereto,

Figure 2 is elevation of one of the hollow chisels, and

Figure 3 is an end view of the cutting end of the chisel.

The grinder comprises a cylindrically shaped body portion 1 having a conically shaped outer end 2, the body portion 1 being embedded as by babbitt or the like, illustrated at within a tapered holding chuck or head a, the babbitthaving an axial bore therein which is internally screw threaded as at 5, by which it may be mounted upon a rotative spindle or shaft 6 actuated in any desired manner.

7 represents a hollow mortising tool com- 40 monly used in wood working machinery the exterior of the cutting bit ofthe ,tool'being I square in cross section and having a round axial bore therethrough. In sharpening the cutting end of this tool upon the grinder the tool is held in axial alignment with f the grinder and crowded against same until'the end of the tool is. completely countersunk by the action of the grinder which will form concaved arcuately shaped cutting edges on the four sides of the'tool, as illustratedxat 8.

If it is desired to lessen the depth of the concaved portion and yet perfectly sharpen each corner of the tool, a tipping of the tool out of axial alignment with the grinderwill accomplish the desired result, as is obvious, such positioning of the tool being illustrated in dotted lines at 9 in Figure l, and it is apparent that a more blunt conically shaped grinder would countersink the tool less, or a sharper one than that shown would countersink the tool more, so thatany desired. edge 11 the toolmay be readily accomplished.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is

A grinding tool comprising a hollow conical holder, a metal mass within the holder, a grinding element having a frustmconical base extending within the smaller end of the holder and embedded in the metal mass, said metal mass having a screw-threaded bore to receive an actuating shaft or spindle.

In testimony whereof we hereunto a'tliX our signatures in the presence of two witnesses.

STANLEY VENGRIN. 7 JOHN M. JOHNSON. .Vitnesses V G. D. Donnnow A. M. CAMPBELL. 

